The Genetics of Sphingolipid Hydrolases and Sphingolipid Storage Diseases

The metabolism of sphingolipids is complex and carefully regulated. Abnormal metabolism can have profound effects on cellular function, leading to enhanced cell death, proliferation, and/or abnormal cell differentiation. This chapter focuses on the genetics of sphingolipid storage diseases and related hydrolytic enzymes. It reviews each of the diseases/enzymes with an emphasis on the importance of genetic mutations in disease. The chapter presents the acid ceramidase deficiency: Farber disease, acid sphingomyelinase deficiency: types A and B Niemann-Pick disease (NPD), and beta-glucocerebrosidase deficiency: Gaucher disease. It describes the galactocerebrosidase deficiency: Krabbe disease/globoid cell leukodystrophy (GLD), arylsulfatase a deficiency: metachromatic leukodystrophy (MLD), beta-galactosidase deficiency: GM1 gangliosidosis and hexosaminidase A and B deficiency: GM2 gangliosidoses. The primary substrates for Hex A and Hex B are glycoproteins, oligosaccharides, glycosaminoglycans, and glycolipids, including the ganglioside GM2 when complexed with the GM2 activator protein.